A new study by climate change scientists has been published in Science, and aims to address claims that the apparent "slowdown" of global warming over the past decade invalidates the concept of man-made climate change. While the slowdown is indeed real, the study highlights what the authors characterise as a "false pause" in the warming of the planet -- something that is likely caused by the interactions of the oceans -- but suggests that temperatures will very soon begin to rise again.
The broad conclusion of the study finds that the cool temperatures of the Pacific Ocean have essentially been offsetting the effects of man-made global warming. As reported by Science, it is known that temperatures in the Pacific Ocean switch between cool and warm as part of a two-decade cycle, called the Pacific Decadal Oscillation, which incorporates the more famous, and more frequent, El Nino warming and cooling processes. The last El Nino event in the late 1990s was part of an ongoing Pacific cool phase. When this phase comes to an end, and a transition to a warmer phase occurs, the "false pause" will be over, and warming will accelerate once more. The "pause" is considered "false" because 14 of the 15 hottest years on record have occurred since the year 2000.
The lead author of the study, Byron A Steinman, explained the implications of the new research to the Guardian.
"It [the new paper] has important implications for understanding the slowdown. I think probably the biggest thing that people should understand is there is randomness in the climate system. The recent slowdown in no way invalidates the idea that continued burning of fossil fuels will increase the Earth's surface temperature and pose a substantial burden on human society."
Writing for Real Climate, co-author of the study Michael E Mann described how the natural processes found by this research can be seen to interact with the problematic man-made changes.
"Our conclusion that natural cooling in the Pacific is a principal contributor to the recent slowdown in large-scale warming is consistent with some other recent studies, including a study I commented on previously showing that stronger-than-normal winds in the tropical Pacific during the past decade have lead to increased upwelling of cold deep water in the eastern equatorial Pacific. [It] is perhaps the most worrying implication of our study, for it implies that the 'false pause' may simply have been a cause of false complacency when it comes to averting dangerous climate change."
Climate change scientists hope that studies such as these will keep attention focused on the 2015 United Nations Climate Change Conference planned for Paris in December. The event aims to create a legally binding agreement, signed by all the nations of the world, to take urgent action on global warming.
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